Lin Nagano (Helena) and Siren Wenruochu (Dawn) who were forced to become pirates
The people devoured by the Siren all have evil hearts. Helena is the first person they have ever seen with a pure and good soul, so she is allowed to stay in the Siren's territory as an exception.
There are multiple ending branches, and the characters in different endings may be biased.
There are lilies, micro-terrors, and deep-sea elements.
Purpose: Interpret the unknown secret